Tools for narrative and expository writing:

A great tool for brainstorming
Thinklinkr: An outlining tool that can also be used to collaborate on outlines
How to create an on-line peer sharing and editing site using Ning Groups
How to write a novel on Twitter
How to write a cellphone novel
20+ great ways to use simple, on-line tools for creative writing--very imaginative

Great First Lines--a site that has first lines from lots of novels and short stories; great for inspiration

Imagination prompt generator (part of the Creativity Portal)

Etherpad: Real-time, on-line document collaboration (with chat); Typewith.me is another, simpler version of this; there's now also PrimaryPad, which is designed to replace Etherpad; also, TitanPad. Also Crocodocs.

My Webspiration: Inspiration + collaboration features

ShowBeyond: Good for digital storytelling
Panraven: another good digital storytelling tool built around a scrapbook model

ThyNews: Create an on-line newspaper

Lightning Bug--an on-line suite of tools for developing story ideas

Storyboard templates

Folding Story -- an odd but interesting collaborative storytelling site; worth exploring.

Writing Tools